In elevators, the speed of the elevator can is monitored in order to avoid dangerous situations where car speed exceeds a fixed limit of safe speed set for the elevator or a limit varying in the function of car position. Overspeed might lead to situation where safe stopping is not anymore possible. A most dangerous situation would be free fall of the elevator car, for instance. Overspeed is conventionally monitored with a device known as overspeed governor. The device is arranged to bring the elevator car into a stop in case overspeed is detected. The overspeed governor typically includes a rope loop separate from hoisting ropes, which rope loop passes around rope wheels mounted in proximity of opposite ends of the elevator hoistway, and which rope loop rotates moved by the car. The rope loop is connected to a safety gear link mounted on the car. One of the rope wheels is provided with a complex mechanical mechanism arranged to activate to arrest the rope wheel in case its rotation speed exceeds a limit. Sudden stop of the rope wheel causes pull via the rope loop to the safety gear link moving along the car, which triggers actuation the safety gear mounted on the car.
A drawback of the existing solutions is that they require equipping the elevator with an additional fast moving component, i.e. the rotating rope loop, as well as the stationary rope wheels in proximity of the ends of the hoistway. An additional fast moving component, as well as wheels mounted in the limited space bring layout challenges and exceed complexity of the elevator construction. A further drawback has been that the mechanism of the overspeed governor wheel, as well as the force transmission to the safety gear have been complicated or expensive to manufacture.